Marc Boucher | 5054e85 | 2002-01-19 10:59:12 +0000 | [diff] [blame^] | 1 | /* Shared library add-on to iptables for conntrack matching support. |
| 2 | * GPL (C) 2001 Marc Boucher (marc@mbsi.ca). |
| 3 | */ |
| 4 | |
| 5 | #include <stdio.h> |
| 6 | #include <netdb.h> |
| 7 | #include <string.h> |
| 8 | #include <stdlib.h> |
| 9 | #include <getopt.h> |
| 10 | #include <ctype.h> |
| 11 | #include <iptables.h> |
| 12 | #include <linux/netfilter_ipv4/ip_conntrack.h> |
| 13 | #include <linux/netfilter_ipv4/ip_conntrack_tuple.h> |
| 14 | #include <linux/netfilter_ipv4/ipt_conntrack.h> |
| 15 | |
| 16 | /* Function which prints out usage message. */ |
| 17 | static void |
| 18 | help(void) |
| 19 | { |
| 20 | printf( |
| 21 | "conntrack match v%s options:\n" |
| 22 | " [!] --ctstate [INVALID|ESTABLISHED|NEW|RELATED|SNAT|DNAT][,...]\n" |
| 23 | " State(s) to match\n" |
| 24 | " [!] --ctproto proto Protocol to match; by number or name, eg. `tcp'\n" |
| 25 | " --ctorigsrc [!] address[/mask]\n" |
| 26 | " Original source specification\n" |
| 27 | " --ctorigdst [!] address[/mask]\n" |
| 28 | " Original destination specification\n" |
| 29 | " --ctreplsrc [!] address[/mask]\n" |
| 30 | " Reply source specification\n" |
| 31 | " --ctrepldst [!] address[/mask]\n" |
| 32 | " Reply destination specification\n" |
| 33 | " [!] --ctstatus [NONE|EXPECTED|SEEN_REPLY|ASSURED][,...]\n" |
| 34 | " Status(es) to match\n" |
| 35 | " [!] --ctexpire time[:time] Match remaining lifetime in seconds against\n" |
| 36 | " value or range of values (inclusive)\n" |
| 37 | "\n", NETFILTER_VERSION); |
| 38 | } |
| 39 | |
| 40 | |
| 41 | |
| 42 | static struct option opts[] = { |
| 43 | { "ctstate", 1, 0, '1' }, |
| 44 | { "ctproto", 1, 0, '2' }, |
| 45 | { "ctorigsrc", 1, 0, '3' }, |
| 46 | { "ctorigdst", 1, 0, '4' }, |
| 47 | { "ctreplsrc", 1, 0, '5' }, |
| 48 | { "ctrepldst", 1, 0, '6' }, |
| 49 | { "ctstatus", 1, 0, '7' }, |
| 50 | { "ctexpire", 1, 0, '8' }, |
| 51 | {0} |
| 52 | }; |
| 53 | |
| 54 | /* Initialize the match. */ |
| 55 | static void |
| 56 | init(struct ipt_entry_match *m, unsigned int *nfcache) |
| 57 | { |
| 58 | /* Can't cache this */ |
| 59 | *nfcache |= NFC_UNKNOWN; |
| 60 | } |
| 61 | |
| 62 | static int |
| 63 | parse_state(const char *state, size_t strlen, struct ipt_conntrack_info *sinfo) |
| 64 | { |
| 65 | if (strncasecmp(state, "INVALID", strlen) == 0) |
| 66 | sinfo->statemask |= IPT_CONNTRACK_STATE_INVALID; |
| 67 | else if (strncasecmp(state, "NEW", strlen) == 0) |
| 68 | sinfo->statemask |= IPT_CONNTRACK_STATE_BIT(IP_CT_NEW); |
| 69 | else if (strncasecmp(state, "ESTABLISHED", strlen) == 0) |
| 70 | sinfo->statemask |= IPT_CONNTRACK_STATE_BIT(IP_CT_ESTABLISHED); |
| 71 | else if (strncasecmp(state, "RELATED", strlen) == 0) |
| 72 | sinfo->statemask |= IPT_CONNTRACK_STATE_BIT(IP_CT_RELATED); |
| 73 | else if (strncasecmp(state, "SNAT", strlen) == 0) |
| 74 | sinfo->statemask |= IPT_CONNTRACK_STATE_SNAT; |
| 75 | else if (strncasecmp(state, "DNAT", strlen) == 0) |
| 76 | sinfo->statemask |= IPT_CONNTRACK_STATE_DNAT; |
| 77 | else |
| 78 | return 0; |
| 79 | return 1; |
| 80 | } |
| 81 | |
| 82 | static void |
| 83 | parse_states(const char *arg, struct ipt_conntrack_info *sinfo) |
| 84 | { |
| 85 | const char *comma; |
| 86 | |
| 87 | while ((comma = strchr(arg, ',')) != NULL) { |
| 88 | if (comma == arg || !parse_state(arg, comma-arg, sinfo)) |
| 89 | exit_error(PARAMETER_PROBLEM, "Bad ctstate `%s'", arg); |
| 90 | arg = comma+1; |
| 91 | } |
| 92 | |
| 93 | if (strlen(arg) == 0 || !parse_state(arg, strlen(arg), sinfo)) |
| 94 | exit_error(PARAMETER_PROBLEM, "Bad ctstate `%s'", arg); |
| 95 | } |
| 96 | |
| 97 | static int |
| 98 | parse_status(const char *status, size_t strlen, struct ipt_conntrack_info *sinfo) |
| 99 | { |
| 100 | if (strncasecmp(status, "NONE", strlen) == 0) |
| 101 | sinfo->statusmask |= 0; |
| 102 | else if (strncasecmp(status, "EXPECTED", strlen) == 0) |
| 103 | sinfo->statusmask |= IPS_EXPECTED; |
| 104 | else if (strncasecmp(status, "SEEN_REPLY", strlen) == 0) |
| 105 | sinfo->statusmask |= IPS_SEEN_REPLY; |
| 106 | else if (strncasecmp(status, "ASSURED", strlen) == 0) |
| 107 | sinfo->statusmask |= IPS_ASSURED; |
| 108 | else |
| 109 | return 0; |
| 110 | return 1; |
| 111 | } |
| 112 | |
| 113 | static void |
| 114 | parse_statuses(const char *arg, struct ipt_conntrack_info *sinfo) |
| 115 | { |
| 116 | const char *comma; |
| 117 | |
| 118 | while ((comma = strchr(arg, ',')) != NULL) { |
| 119 | if (comma == arg || !parse_status(arg, comma-arg, sinfo)) |
| 120 | exit_error(PARAMETER_PROBLEM, "Bad ctstatus `%s'", arg); |
| 121 | arg = comma+1; |
| 122 | } |
| 123 | |
| 124 | if (strlen(arg) == 0 || !parse_status(arg, strlen(arg), sinfo)) |
| 125 | exit_error(PARAMETER_PROBLEM, "Bad ctstatus `%s'", arg); |
| 126 | } |
| 127 | |
| 128 | |
| 129 | static unsigned long |
| 130 | parse_expire(const char *s) |
| 131 | { |
| 132 | unsigned int len; |
| 133 | |
| 134 | if (string_to_number(s, 0, 0xFFFFFFFF, &len) == -1) |
| 135 | exit_error(PARAMETER_PROBLEM, "expire value invalid: `%s'\n", s); |
| 136 | else |
| 137 | return len; |
| 138 | } |
| 139 | |
| 140 | /* If a single value is provided, min and max are both set to the value */ |
| 141 | static void |
| 142 | parse_expires(const char *s, struct ipt_conntrack_info *sinfo) |
| 143 | { |
| 144 | char *buffer; |
| 145 | char *cp; |
| 146 | |
| 147 | buffer = strdup(s); |
| 148 | if ((cp = strchr(buffer, ':')) == NULL) |
| 149 | sinfo->expires_min = sinfo->expires_max = parse_expire(buffer); |
| 150 | else { |
| 151 | *cp = '\0'; |
| 152 | cp++; |
| 153 | |
| 154 | sinfo->expires_min = buffer[0] ? parse_expire(buffer) : 0; |
| 155 | sinfo->expires_max = cp[0] ? parse_expire(cp) : 0xFFFFFFFF; |
| 156 | } |
| 157 | free(buffer); |
| 158 | |
| 159 | if (sinfo->expires_min > sinfo->expires_max) |
| 160 | exit_error(PARAMETER_PROBLEM, |
| 161 | "expire min. range value `%lu' greater than max. " |
| 162 | "range value `%lu'", sinfo->expires_min, sinfo->expires_max); |
| 163 | |
| 164 | } |
| 165 | |
| 166 | /* Function which parses command options; returns true if it |
| 167 | ate an option */ |
| 168 | static int |
| 169 | parse(int c, char **argv, int invert, unsigned int *flags, |
| 170 | const struct ipt_entry *entry, |
| 171 | unsigned int *nfcache, |
| 172 | struct ipt_entry_match **match) |
| 173 | { |
| 174 | struct ipt_conntrack_info *sinfo = (struct ipt_conntrack_info *)(*match)->data; |
| 175 | char *protocol = NULL; |
| 176 | unsigned int naddrs = 0; |
| 177 | struct in_addr *addrs = NULL; |
| 178 | |
| 179 | |
| 180 | switch (c) { |
| 181 | case '1': |
| 182 | if (check_inverse(optarg, &invert)) |
| 183 | optind++; |
| 184 | |
| 185 | parse_states(argv[optind-1], sinfo); |
| 186 | if (invert) { |
| 187 | sinfo->invflags |= IPT_CONNTRACK_STATE; |
| 188 | } |
| 189 | sinfo->flags |= IPT_CONNTRACK_STATE; |
| 190 | break; |
| 191 | |
| 192 | case '2': |
| 193 | if (check_inverse(optarg, &invert)) |
| 194 | optind++; |
| 195 | |
| 196 | if(invert) |
| 197 | sinfo->invflags |= IPT_CONNTRACK_PROTO; |
| 198 | |
| 199 | /* Canonicalize into lower case */ |
| 200 | for (protocol = argv[optind-1]; *protocol; protocol++) |
| 201 | *protocol = tolower(*protocol); |
| 202 | |
| 203 | protocol = argv[optind-1]; |
| 204 | sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.protonum = parse_protocol(protocol); |
| 205 | |
| 206 | if (sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.protonum == 0 |
| 207 | && (sinfo->invflags & IPT_INV_PROTO)) |
| 208 | exit_error(PARAMETER_PROBLEM, |
| 209 | "rule would never match protocol"); |
| 210 | |
| 211 | sinfo->flags |= IPT_CONNTRACK_PROTO; |
| 212 | break; |
| 213 | |
| 214 | case '3': |
| 215 | if (check_inverse(optarg, &invert)) |
| 216 | optind++; |
| 217 | |
| 218 | if (invert) |
| 219 | sinfo->invflags |= IPT_CONNTRACK_ORIGSRC; |
| 220 | |
| 221 | parse_hostnetworkmask(argv[optind-1], &addrs, |
| 222 | &sinfo->sipmsk[IP_CT_DIR_ORIGINAL], |
| 223 | &naddrs); |
| 224 | if(naddrs > 1) |
| 225 | exit_error(PARAMETER_PROBLEM, |
| 226 | "multiple IP addresses not allowed"); |
| 227 | |
| 228 | if(naddrs == 1) { |
| 229 | sinfo->tuple[IP_CT_DIR_ORIGINAL].src.ip = addrs[0].s_addr; |
| 230 | } |
| 231 | |
| 232 | sinfo->flags |= IPT_CONNTRACK_ORIGSRC; |
| 233 | break; |
| 234 | |
| 235 | case '4': |
| 236 | if (check_inverse(optarg, &invert)) |
| 237 | optind++; |
| 238 | |
| 239 | if (invert) |
| 240 | sinfo->invflags |= IPT_CONNTRACK_ORIGDST; |
| 241 | |
| 242 | parse_hostnetworkmask(argv[optind-1], &addrs, |
| 243 | &sinfo->dipmsk[IP_CT_DIR_ORIGINAL], |
| 244 | &naddrs); |
| 245 | if(naddrs > 1) |
| 246 | exit_error(PARAMETER_PROBLEM, |
| 247 | "multiple IP addresses not allowed"); |
| 248 | |
| 249 | if(naddrs == 1) { |
| 250 | sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.ip = addrs[0].s_addr; |
| 251 | } |
| 252 | |
| 253 | sinfo->flags |= IPT_CONNTRACK_ORIGDST; |
| 254 | break; |
| 255 | |
| 256 | case '5': |
| 257 | if (check_inverse(optarg, &invert)) |
| 258 | optind++; |
| 259 | |
| 260 | if (invert) |
| 261 | sinfo->invflags |= IPT_CONNTRACK_REPLSRC; |
| 262 | |
| 263 | parse_hostnetworkmask(argv[optind-1], &addrs, |
| 264 | &sinfo->sipmsk[IP_CT_DIR_REPLY], |
| 265 | &naddrs); |
| 266 | if(naddrs > 1) |
| 267 | exit_error(PARAMETER_PROBLEM, |
| 268 | "multiple IP addresses not allowed"); |
| 269 | |
| 270 | if(naddrs == 1) { |
| 271 | sinfo->tuple[IP_CT_DIR_REPLY].src.ip = addrs[0].s_addr; |
| 272 | } |
| 273 | |
| 274 | sinfo->flags |= IPT_CONNTRACK_REPLSRC; |
| 275 | break; |
| 276 | |
| 277 | case '6': |
| 278 | if (check_inverse(optarg, &invert)) |
| 279 | optind++; |
| 280 | |
| 281 | if (invert) |
| 282 | sinfo->invflags |= IPT_CONNTRACK_REPLDST; |
| 283 | |
| 284 | parse_hostnetworkmask(argv[optind-1], &addrs, |
| 285 | &sinfo->dipmsk[IP_CT_DIR_REPLY], |
| 286 | &naddrs); |
| 287 | if(naddrs > 1) |
| 288 | exit_error(PARAMETER_PROBLEM, |
| 289 | "multiple IP addresses not allowed"); |
| 290 | |
| 291 | if(naddrs == 1) { |
| 292 | sinfo->tuple[IP_CT_DIR_REPLY].dst.ip = addrs[0].s_addr; |
| 293 | } |
| 294 | |
| 295 | sinfo->flags |= IPT_CONNTRACK_REPLDST; |
| 296 | break; |
| 297 | |
| 298 | case '7': |
| 299 | if (check_inverse(optarg, &invert)) |
| 300 | optind++; |
| 301 | |
| 302 | parse_statuses(argv[optind-1], sinfo); |
| 303 | if (invert) { |
| 304 | sinfo->invflags |= IPT_CONNTRACK_STATUS; |
| 305 | } |
| 306 | sinfo->flags |= IPT_CONNTRACK_STATUS; |
| 307 | break; |
| 308 | |
| 309 | case '8': |
| 310 | if (check_inverse(optarg, &invert)) |
| 311 | optind++; |
| 312 | |
| 313 | parse_expires(argv[optind-1], sinfo); |
| 314 | if (invert) { |
| 315 | sinfo->invflags |= IPT_CONNTRACK_EXPIRES; |
| 316 | } |
| 317 | sinfo->flags |= IPT_CONNTRACK_EXPIRES; |
| 318 | break; |
| 319 | |
| 320 | default: |
| 321 | return 0; |
| 322 | } |
| 323 | |
| 324 | *flags = sinfo->flags; |
| 325 | return 1; |
| 326 | } |
| 327 | |
| 328 | static void |
| 329 | final_check(unsigned int flags) |
| 330 | { |
| 331 | if (!flags) |
| 332 | exit_error(PARAMETER_PROBLEM, "You must specify one or more options"); |
| 333 | } |
| 334 | |
| 335 | static void |
| 336 | print_state(unsigned int statemask) |
| 337 | { |
| 338 | const char *sep = ""; |
| 339 | |
| 340 | if (statemask & IPT_CONNTRACK_STATE_INVALID) { |
| 341 | printf("%sINVALID", sep); |
| 342 | sep = ","; |
| 343 | } |
| 344 | if (statemask & IPT_CONNTRACK_STATE_BIT(IP_CT_NEW)) { |
| 345 | printf("%sNEW", sep); |
| 346 | sep = ","; |
| 347 | } |
| 348 | if (statemask & IPT_CONNTRACK_STATE_BIT(IP_CT_RELATED)) { |
| 349 | printf("%sRELATED", sep); |
| 350 | sep = ","; |
| 351 | } |
| 352 | if (statemask & IPT_CONNTRACK_STATE_BIT(IP_CT_ESTABLISHED)) { |
| 353 | printf("%sESTABLISHED", sep); |
| 354 | sep = ","; |
| 355 | } |
| 356 | if (statemask & IPT_CONNTRACK_STATE_SNAT) { |
| 357 | printf("%sSNAT", sep); |
| 358 | sep = ","; |
| 359 | } |
| 360 | if (statemask & IPT_CONNTRACK_STATE_DNAT) { |
| 361 | printf("%sDNAT", sep); |
| 362 | sep = ","; |
| 363 | } |
| 364 | printf(" "); |
| 365 | } |
| 366 | |
| 367 | static void |
| 368 | print_status(unsigned int statusmask) |
| 369 | { |
| 370 | const char *sep = ""; |
| 371 | |
| 372 | if (statusmask & IPS_EXPECTED) { |
| 373 | printf("%sEXPECTED", sep); |
| 374 | sep = ","; |
| 375 | } |
| 376 | if (statusmask & IPS_SEEN_REPLY) { |
| 377 | printf("%sSEEN_REPLY", sep); |
| 378 | sep = ","; |
| 379 | } |
| 380 | if (statusmask & IPS_ASSURED) { |
| 381 | printf("%sASSURED", sep); |
| 382 | sep = ","; |
| 383 | } |
| 384 | if (statusmask == 0) { |
| 385 | printf("%sNONE", sep); |
| 386 | sep = ","; |
| 387 | } |
| 388 | printf(" "); |
| 389 | } |
| 390 | |
| 391 | static void |
| 392 | print_addr(struct in_addr *addr, struct in_addr *mask, int inv, int numeric) |
| 393 | { |
| 394 | char buf[BUFSIZ]; |
| 395 | |
| 396 | if (inv) |
| 397 | fputc('!', stdout); |
| 398 | |
| 399 | if (mask->s_addr == 0L && !numeric) |
| 400 | printf("%s ", "anywhere"); |
| 401 | else { |
| 402 | if (numeric) |
| 403 | sprintf(buf, "%s", addr_to_dotted(addr)); |
| 404 | else |
| 405 | sprintf(buf, "%s", addr_to_anyname(addr)); |
| 406 | strcat(buf, mask_to_dotted(mask)); |
| 407 | printf("%s ", buf); |
| 408 | } |
| 409 | } |
| 410 | |
| 411 | /* Saves the matchinfo in parsable form to stdout. */ |
| 412 | static void |
| 413 | matchinfo_print(const struct ipt_ip *ip, const struct ipt_entry_match *match, int numeric, const char *optpfx) |
| 414 | { |
| 415 | struct ipt_conntrack_info *sinfo = (struct ipt_conntrack_info *)match->data; |
| 416 | |
| 417 | if(sinfo->flags & IPT_CONNTRACK_STATE) { |
| 418 | printf("%sctstate ", optpfx); |
| 419 | if (sinfo->invflags & IPT_CONNTRACK_STATE) |
| 420 | fputc('!', stdout); |
| 421 | print_state(sinfo->statemask); |
| 422 | } |
| 423 | |
| 424 | if(sinfo->flags & IPT_CONNTRACK_ORIGSRC) { |
| 425 | printf("%sctorigsrc ", optpfx); |
| 426 | |
| 427 | print_addr( |
| 428 | (struct in_addr *)&sinfo->tuple[IP_CT_DIR_ORIGINAL].src.ip, |
| 429 | &sinfo->sipmsk[IP_CT_DIR_ORIGINAL], |
| 430 | sinfo->invflags & IPT_CONNTRACK_ORIGSRC, |
| 431 | numeric); |
| 432 | } |
| 433 | |
| 434 | if(sinfo->flags & IPT_CONNTRACK_ORIGDST) { |
| 435 | printf("%sctorigdst ", optpfx); |
| 436 | |
| 437 | print_addr( |
| 438 | (struct in_addr *)&sinfo->tuple[IP_CT_DIR_ORIGINAL].dst.ip, |
| 439 | &sinfo->dipmsk[IP_CT_DIR_ORIGINAL], |
| 440 | sinfo->invflags & IPT_CONNTRACK_ORIGDST, |
| 441 | numeric); |
| 442 | } |
| 443 | |
| 444 | if(sinfo->flags & IPT_CONNTRACK_REPLSRC) { |
| 445 | printf("%sctorigsrc ", optpfx); |
| 446 | |
| 447 | print_addr( |
| 448 | (struct in_addr *)&sinfo->tuple[IP_CT_DIR_REPLY].src.ip, |
| 449 | &sinfo->sipmsk[IP_CT_DIR_REPLY], |
| 450 | sinfo->invflags & IPT_CONNTRACK_REPLSRC, |
| 451 | numeric); |
| 452 | } |
| 453 | |
| 454 | if(sinfo->flags & IPT_CONNTRACK_REPLDST) { |
| 455 | printf("%sctorigdst ", optpfx); |
| 456 | |
| 457 | print_addr( |
| 458 | (struct in_addr *)&sinfo->tuple[IP_CT_DIR_REPLY].dst.ip, |
| 459 | &sinfo->dipmsk[IP_CT_DIR_REPLY], |
| 460 | sinfo->invflags & IPT_CONNTRACK_REPLDST, |
| 461 | numeric); |
| 462 | } |
| 463 | |
| 464 | if(sinfo->flags & IPT_CONNTRACK_STATUS) { |
| 465 | printf("%sctstatus ", optpfx); |
| 466 | if (sinfo->invflags & IPT_CONNTRACK_STATE) |
| 467 | fputc('!', stdout); |
| 468 | print_status(sinfo->statusmask); |
| 469 | } |
| 470 | |
| 471 | if(sinfo->flags & IPT_CONNTRACK_EXPIRES) { |
| 472 | printf("%sctexpire ", optpfx); |
| 473 | if (sinfo->invflags & IPT_CONNTRACK_EXPIRES) |
| 474 | fputc('!', stdout); |
| 475 | |
| 476 | if (sinfo->expires_max == sinfo->expires_min) |
| 477 | printf("%lu ", sinfo->expires_min); |
| 478 | else |
| 479 | printf("%lu:%lu ", sinfo->expires_min, sinfo->expires_max); |
| 480 | } |
| 481 | } |
| 482 | |
| 483 | /* Prints out the matchinfo. */ |
| 484 | static void |
| 485 | print(const struct ipt_ip *ip, |
| 486 | const struct ipt_entry_match *match, |
| 487 | int numeric) |
| 488 | { |
| 489 | matchinfo_print(ip, match, numeric, ""); |
| 490 | } |
| 491 | |
| 492 | /* Saves the matchinfo in parsable form to stdout. */ |
| 493 | static void save(const struct ipt_ip *ip, const struct ipt_entry_match *match) |
| 494 | { |
| 495 | matchinfo_print(ip, match, 0, "--"); |
| 496 | } |
| 497 | |
| 498 | static |
| 499 | struct iptables_match conntrack |
| 500 | = { NULL, |
| 501 | "conntrack", |
| 502 | NETFILTER_VERSION, |
| 503 | IPT_ALIGN(sizeof(struct ipt_conntrack_info)), |
| 504 | IPT_ALIGN(sizeof(struct ipt_conntrack_info)), |
| 505 | &help, |
| 506 | &init, |
| 507 | &parse, |
| 508 | &final_check, |
| 509 | &print, |
| 510 | &save, |
| 511 | opts |
| 512 | }; |
| 513 | |
| 514 | void _init(void) |
| 515 | { |
| 516 | register_match(&conntrack); |
| 517 | } |